Synthetic Voice & Audio Localization

The problem

A generic TTS system reading a translated script produces a voice that reads a translation. The sentence structure was designed for written English; the TTS engine reads it in French. Native speakers hear the difference immediately: the rhythm is wrong, the word choices are slightly formal or slightly odd, the sentence breaks land in unexpected places.

Translation and spoken language are different skills. A script for voice delivery needs to be written with speaking in mind: shorter sentences, natural spoken phrasing, rhythm that sounds like speech rather than prose. Translating a script that was already written for speaking is closer to writing for speaking than translating documentation, but translating an English script into a French equivalent that sounds naturally spoken in French requires a linguist who is also a copywriter.

Voice synthesis is also not uniform across languages. The same TTS platform produces substantially different quality for English, French, and Polish. Voice model selection, prosody parameters, and phoneme handling all need attention per locale, particularly for brand names, product names, and technical vocabulary that the base model will not have seen in training.

How we approach it

We work at two levels: script and synthesis.

For the script, we start with adaptation, not translation. The source English script is a reference for meaning, tone, and pacing. The target language script is written by a native speaker who understands both the content and the voice delivery context. Sentence structure, natural spoken idioms, and the rhythm of the language are considered as primary constraints, not as concerns to address after the translation is done.

For technical and brand vocabulary, we build a phoneme guide per locale: how the product name should be pronounced, how abbreviations should be expanded for speech, how numbers and dates should be read aloud. This is especially important for IVR and voice UI, where the caller will hear the name and need to respond to it or remember it.

For synthesis, we evaluate TTS options per locale (not all platforms are equal in all languages) and configure the parameters (speed, pitch, prosody) to match the register of the adapted script. We test critical vocabulary against the phoneme guide before final rendering.

Delivery includes both the adapted script (for client review and future updates) and the synthesized audio files in the specified format.